Hellboy: 20 Easter Eggs And References Explained
15. Ogdru Jahad
Given there is only one dragon in the Hellboy source material that actually looks like a dragon - the other being the nickname of a magician - it's safe to say that the wyvern Hellboy rides in Neil Marshall's film is a reference to the Ogdru Jahad, an evil entity that is sealed away by the magic contained in Hellboy's right hand.
Nimue briefly turns into a similar dragon when possessed by the Jahad, so there's also a very real chance the dragon could be in reference to this. Either way, the creature features majorly in a potential negative future, should Hellboy turn to the dark side.